Hi guys! I'm a complete newbie in this area. Very interested in heating my quail barns with clean, renewable, energy. I need to know what material really withstand the test of time? I see a ton of rocket mass heaters that use differentmetals, concretes, and perlite. Most of these burn off. What doesn't burn off?
My idea is to set up a "heat room" that connects my two barns(4' of distance) with a gutter(rain collecting system) and roof, along with a front door and rear venting. My goal is to generate enough heat to cleanly heat both barns(both are 12'x 24') with a fan driven duct system. I need to keep the baby quail barn 70* and the adult quail barn above 45*...
I'm leaning towards the following materials; firebrick, cob, duct.
We have clay soil that is super hard when dry but quicksand texture when wet. Really looking for proven design concepts. Because there's an earthen floor I'm looking for ideas on providing a flood resisted barrier from the ground, as well. Would LOVE some feedback from all you seasoned folk!! (We're in Cashmere Washington and would love to extend housing for experienced help option!!)
You can make riser insulation, or even cast the whole riser, with a mix of perlite and clay (mostly perlite). Thermal cob would have considerable sand added to the clay, somewhere around 3:1 sharp mason's sand to pure clay. You would want to make test bricks of several mixes to see exactly what works for your materials. You might add a bit of straw for tensile strength here, some would say not to. I think it depends on your specific configuration. The outer 2" or so of the mass would be a clay/sand/straw mix (again, try several ratios to see how your materials work best) to hold the whole mass together and reinforce the surface, topped off with an earth or lime plaster for a smooth strong surface.
I was hoping to use it in insulating the riser along with vermiculite or perlite.(I found non-asbestos vermiculite but am having difficulty finding perlite) I also found some fire bricks that I was going to use for my core. The property we're doing this on has very fine sand on it, should I even attempt to use this instead of sand, along with clay and straw, for the thermal mass? My concern is the sand is almost clay-like itself.
I'm leaning towards the thermal mass being bench-like but running the tubing vertical on itself instead of laying along the floor horizontally. If that makes sense? Basically it'd vent (with stove pipe for the first 10 ft) from the barrel along my insulated floor and then I'll brace it through two turns(180*) back up on itself and vent through roof near barrel. Not sure what I'll use for bracing structure to test the unit but will obviously be adding thermal mass between the two levels. It should be tall and thin!
My thought process is, the mass will radiate through the plywood barn wall and organically heat it.
The thermal mass will not radiate effectively through the plywood walls; you would need to remove the plywood in the mass area and let it radiate directly into the spaces on either side. I think what you want instead of ducting winding through the mass is a bell. This is a big hollow masonry box with the heat source entering as low as practical, and the exit at the bottom, so hot air stratifies and gives up its heat to the mass before cooling, dropping, and reaching the chimney connector. This would have next to no flow resistance for a large capacity.
I see you are on the other side of the mountains from Seattle, so you presumably have long cold winters. I think you would want a larger system; perhaps an 8" batch box with its appropriate bell internal surface area would suffice, and put enough heat into the mass with one burn to last for a whole day. (See Peter van den Berg's "Results of the 8" Batch Box Thingy" thread for some guidance.) Do the barns adjoin along their end walls or side walls? The closer the mass is to all parts of the space the better it will work. Fans may give enough circulation, but remember that moving air has a cooling effect.
Interesting idea, Glenn! I spent the last few days looking at concepts for the bell idea and was thoroughly impressed. BUT it brings up even more questions
First, I'm working with a space that is only 6ft high. I'm short so this won't be an issue of clearance for me but may be an issue getting the height to generate enough btu's and then encasing some in mass.
Second, if I stuck to the initial siphon barrel and vented(&insulated with mass) from my core to a second barrel located in 1 barn(3-4 ft distance), then did a cold air return back through mass and exhaust through roof, near first barrel is it hypothetically possible? I understand there may be a ton of variables. One of my concerns is physically cutting into the steel barrels (I only have a hand-held metal wheel grinder) no plasma cutters here!
Lastly, the baby(brooder) barn is my biggest concern, (the babies need heat and we've been a spending $100's of dollars a month to electrically heat with heat bulbs. I will still need bulbs to regulate heat but can hopefully lessen the burden.) running a barrel into there, and using mass to help prolong the radiant, makes a ton of sense to me. Hopefully there's still enough heat to run back through the stove!
Ok! I've been doing a ton more research and have more ideas to run past you guys!
Decided to go ahead and do a RMH vs a bell. A ton of reasons for this but the biggest is length of time a mass will radiate heat. I need this mass to stay warm for a long length of time(overnights plus some). This will be a 4'x15' space that is going to be consumed by the heater. This space is between two barns and will have vents, located near the top of the walls, to each barn that can be closed or open. Organic venting will hopefully be enough to raise the temp. I understand the heater room is going to be insanely hot. the only reason to go in there will be to feed the stove.
What do you think?
Also, my plan is to brace heater room off ground(need to avoid moisture and elevate to barn floor height)... Placing cinder blocks on ground level, then using some commercial pallets(2x6 construction) to form the floor. Then laying down 1/2" plywood(the pallets are almost solid along the top and bottom already). Using misc bricks I'll outline the shape of my core and put a mixture of perlite and clay directly on plywood to insulate. Pack this down? Then add a leveled sand, less then 2" thick. Then place firebricks for my core and riser. Insulate entire thing with clay perlite allowing for clearance around riser for airflow and 2" clearance from top to interior barrel. I have a barrel with the removable lid, what's your experience with them? Worth using for clean out? If so, just cut off bottom?... How do you transition to the 8" piping? I found galvanized 8" HVAC vent that was angled and could be built up and insulated with firebrick and perlite/clay. Worried it might collapse over time, what are the chances if it's properly built up with firebrick and clay/perlite? Found single wall stove pipe that I'd use for the first 48" into mass, to withstand the heat, then probably switch to galvanized pipes, "t"s, and elbow. For roof vents, does anyone have a preference? I found 8" galvanized that's used for simple roof vents but it'd be an almost flush mount with the roof. My roof is sloped galvanized. With my barrel being 2" from my exhaust pipe, do I need to worry about elevating it above the peak or anything? I, obviously, want to avoid back draft as much as possible.
Sorry to make this so long! I'm excited to get started!! I have 90% of my materials!! Then I want to help a friend build one in her greenhouse.
If a bell has the same wall thickness and surface area as a standard RMH bench, it will store the same amount of heat and radiate it just as long. Since you really want to throw the heat sideways in two directions, the vertical bell with large sidewalls will give significantly better results than a horizontal bench that will radiate a majority of its heat upwards. Trying to make a convective heater that works by moving hot air will lose a lot of effectiveness - radiation from a wall directly into the space will work much better. As you want the chick barn warmer than the adult barn, I would actually bulge the bell out a bit into the chick barn so there is more radiating surface exposed there. I would also put a lot of insulation on the bell roof, as you do not want heat going straight up.
The base structure may work, depending on how substantial the pallets are, but it would be much more durable if you can get enough blocks to make the whole base with them. With the amount and duration of heat you are talking about generating, I think your pallets will be at risk of charring and even burning over time. Insulation alone will only slow the passage of heat, not prevent it. You would need an airspace between the insulated base and the pallets so air can circulate and cool off the bottom of the insulation.
My lack of literature on design concepts for the bell is making the idea risky. My application is so niche I'm concerned to be designing myself without an expert on hand(any volunteers?. I also don't have much time to come up with a different plan. I have 2 55 gal drums. Can I use one for the rmh and pipe it directly to a second "settling" barrel, that is barely nudged into the baby barn, and then exhaust the remaining heat through a short bench to finish exhaust out near the first barrel?
Do you have a suggestion for resources?
Should the second barrel have input in top and cool down (exhaust) near base? Does 8" pipe still work? How do I even work this mathematically? I am a business so the pressure, of performance, is on! I feel confident in being capable of cutting a circle in the barrel and using metal heat "cement" for sealing the input/output of the second barrel. I do see the reasoning for your suggestion and am just hesitant due to more unknowns.
The heat barn is going to be VERY insulated and lined with reflective material. The only airflow to and from the heat barn will be when the door is open and when the vents, that we connect the barns to are open.(we were planing on cutting those as we got a feel for output of heat and how responsive each barn is.
Another note: I will use cinder blocks spaced 6" apart as base for the pallet, used as floor for heat barn. These pallets were used in commercial HVAC unit transportation and are rated for 10,000 lbs.
I would be willing to spend a little money on a custom design or a proven concept. Although, our budget will never have enough room for the invaluable information I feel I've already learned!! Your experiences are priceless! I enjoy this adventure and can't wait to find a solution for our quail barn!